Reactions distinguish oxidizing and reducing agents

Steps:

• Aqueous iodide (I⁻) is a reducing agent; no colour change (no I₂ formed) with X means X does not oxidize I⁻, so X is not an oxidizing agent.
• Acidified KMnO₄ (purple) is a strong oxidizing agent; its decolorization by Y means Y reduces MnO₄⁻ to Mn²⁺ (colourless), so Y is a reducing agent.
• Both solutions are colourless, ruling out interference from their own colours in observations.
• Deduction: X lacks oxidizing power, while Y has reducing power.

Why D is correct:

• D states X is not an oxidizing agent (no reaction with I⁻) and Y is a reducing agent (decolorizes KMnO₄), matching the tests' definitions of agent types.

Why the others are wrong:

• A: X shows no reducing/oxidizing activity toward I⁻, so not a reducing agent.
• B: X does not oxidize I⁻, contradicting X as oxidizing agent.
• C: Y reduces KMnO₄, so Y is reducing, not oxidizing.

Final answer: D